Myeloma -> plasma cell malignancy in bone marrow producing Ig.
Presenting signs and symptoms of multiple myeloma (MM) include
(i.e albumin is 1.5 to 2.5 the level of globulin)
[!INFO] Renal involvement in myeloma
"Renal failure is the second most common cause of mortality in patients with multiple myeloma, second only to infections"
[!INFO]
- Pale deposits of amyloid
- Amyloid PAS stains
- Congo red apple green birefringence
- Amyloid fibrils on EM
"Light chain deposition disease", which also can occur with lymphoma and macroglobulinemia, is glomerular deposition of nonpolymerized light chains (ie, without fibrils), generally the constant regions of kappa chains.
"LCDD must be differentiated from AL amyloidosis. LCDD is Congo red negative and is usually IF positive for κ rather than λ light chain.
Moreover, in LCDD the deposits are subendothelial and granular, whereas in amyloidosis they are composed of randomly arranged fibrils."
[!INFO] Kappa Vs. Lamba light chains:
Kappa light chains are coded on chromosome 2.
Lambda light chains are coded on chromosome 22.
"We found that kappa and lambda light chains have very different CDR physicochemical and structural properties, whereas the heavy chains with which they are paired do not differ significantly" Source
Heavy chain deposition (?rarer) in different areas of the kidney can cause immunoglobulin-associated amyloidosis. This usually presents with proteinura or nephrotic syndrome.
Most common clinical manifestations of renal amyloidosis are proteinuria with frequent nephrotic syndrome and progressive renal dysfunction
Replacement or normal bone marrow tissue and alteration of normal marrow environment.
Anemia, high ESR, and low A/G ratio in elderly patients should alert the clinician to investigate along the lines of multiple myeloma. Source
[!INFO] Blood picture in multiple myeloma:
Rouleaux formation - linear aggregates of RBCs.
(different from agglutination in which RBCs form grape like clusters)
A single plasma cells (arrow) is also seen.
